BACKGROUND: Galectin-3 (Gal-3) signaling protein is a unique member of lectin family present at the cell surface, intracellularly in both the nucleus and cytoplasm and extracellularly in the general circulation. Circulating Gal-3 is present in both normal and cancer cells. High levels of circulating Gal-3 have been proven to be associated with inflammation and fibrosis in several acute and chronic conditions, which include neurological degeneration, inflammatory and immune responses, autoimmune diseases, diabetes, heart failure, atherosclerosis, response to infection, wound healing, liver, lung, and kidney disease. Gal-3 is known to regulate many biological activities including cell adhesion, angiogenesis, growth, apoptosis, migration, and metastasis. Rapamycin has been examined alone or in combination with other drugs for treatment of various cancers in clinical studies. Although it has shown promising therapeutic effects, its clinical development was interrupted by poor aqueous solubility and limited preferential distribution. To overcome these limitations, RA has been chemically modified to hydrophilic analogues, such as everolimus (EV). However, all these approaches can only partially increase the solubility, but has little effect on the blood distribution and pharmacokinetics. Therefore, it is necessary to explore other RA conjugates to improve aqueous solubility and tissue distribution profile. Recently we reported that RP-MPEG inhibits the growth of various cancer cell lines by acting on mammalian target of RP (mTOR) receptor site and it can be used for gastric cancer.
OBJECTIVE: To construct various molecular weight RP-MPEG by replacing MPEG chain in 40-O-(2- hydroxyethyl) position of the EV and analyze their binding affinity to Gal-3.
METHODS: The chemical structures of various molecular weight RP-MPEG were built using ChemSketch software. The molecular docking study was performed to find the best probable structure of RP-MPEG for competitive inhibition of the CRD, based on the interaction score. For that purpose, the 3D structures of RP and EV were obtained from NCBI PubChem compound database, where the structural protein-co-crystallized ligand complex of Gal-3 (TD2, as a native ligand) was retrieved from RCSB Protein Data Bank. All structures of the selected compounds, served as molecules for molecular modeling, were optimized through MOE.2014 software before docking. Hydrogen atoms and partial charges were added to the protein. Protein minimization was performed in gas solvation with the side chains, keeping it rigid and the ligand flexible. The selected site was isolated and minimized, followed by protonating the protein. The 3D ligands were minimized using MMFF94x with cutoffs of 10 to 12 Å. The hydrogens and charges were fixed, and the RMS gradient was set to 0.001 kcal/mol. The docking results were analyzed to identify and assess the binding affinity of these compounds to CRD using drug discovery software.
RESULTS: Our results indicated that RP-MPEG with MW 1178.51 g/mol has a logP value of 3.79 and has possessed the strongest binding affinity toward CRD of Gal-3 with a docking score of -6.87. Compared with TD2, there were additional close contacts for RP-MPEG (MW 1178.51 g/mol), coming from three hydrogen bonds with Asp148, Arg162, and Arg144 which suggest that this ligand is a strong competitive inhibitor among the other molecules for Gal-3.
CONCLUSION: RP-MPEG with the MW 1178.51 g/mol could be a promising blocker for various biological action of Gal-3 includes profibrotic activity, modulation of immune responses and inflammatory responses to cancer that contributes to neoplastic transformation, angiogenesis and metastasis. Other: The 95% confidence intervals (CIs) of the binding affinity (according to their mean and standard errors) were estimated with 2.5 and 97.5 percentile as the lower and upper bounds.
OBJECTIVE: Complexation of rHuKGF with mucoadhesive low molecular weight chitosan to protect rHuKGF from proteolysis and investigate the effect of chitosan-rHuKGF complex on the proliferation rate of FHs 74 Int cells.
METHODS: The interaction between chitosan and rHuKGF was studied by molecular docking. Malvern ZetaSizer Nano Zs and Fourier-Transform Infrared spectroscopy (FTIR) tests were carried out to characterize the chitosan-rHuKGF complex. In addition, SDS-PAGE was performed to investigate the interaction between chitosan-rHuKGF complex and pepsin. The effect of chitosan-rHuKGF complex on the proliferation rate of FHs 74 Int cells was studied by MTT assay.
RESULTS: Chitosan-rHuKGF complex was formed through the hydrogen bonding proven by the docking studies. A stable chitosan-rHuKGF complex was formed at pH 4.5 and was protected from proteolysis and assessed by SDS PAGE. According to the MTT assay results, chitosan-rHuKGF complex increased the cell proliferation rate of FHs 74 Int cells.
CONCLUSION: The developed complex improved the stability and the biological function of rHuKGF.
MATERIALS AND METHODS: As a prerequisite for this, the solubility of the drug was assessed in media of different pH (1.2-7.4), and surfactant concentrations of 0.5-1.5% (w/v) sodium lauryl sulfate (SLS) in water, and pH 7.4 phosphate buffer. The dissolved drug concentration in each medium was quantified by UV analysis at 280 nm wavelength.
RESULTS: The drug solubility was found to be high at a pH of 1.2 and 7.4. The media with surfactant enhanced solubility of the drug by approximately 17-fold and exhibited better sink conditions. The discriminative power of the developed dissolution medium (i.e., 1% w/v SLS in pH 7.4) was determined by performing in vitro dissolution studies of the prepared THC tablets and comparing their release profiles using fit factors (f1 and f2). The results of the fit factor comparisons made between the dissolution profiles of THC tablets proved the discriminative ability of the medium. The validation of the developed dissolution method was performed by international guidelines and the method showed specificity, linearity, accuracy, and precision within the acceptable range.
CONCLUSION: The proposed dissolution method was found to be adequate for the routine quality control analysis of THC, as there is no specified dissolution method for the drug in the pharmacopoeia.
OBJECTIVE: Formulation of methacrylic acid-methyl methacrylate copolymer-coated capsules filled with chitosan nanoparticles loaded with rHuKGF for oral delivery.
METHODS: We report on chitosan nanoparticles (CNPs) with diameter < 200 nm, prepared by ionic gelation, loaded with rHuKGF and filled in methacrylic acid-methyl methacrylate copolymercoated capsules for oral delivery. The pharmacokinetic parameters were determined based on the serum levels of rHuKGF, following a single intravenous (IV) or oral dosages using a rabbit model. Furthermore, fluorescent microscope imaging was conducted to investigate the cellular uptake of the rhodamine-labelled rHuKGF-loaded nanoparticles. The proliferation effect of the formulation on FHs 74 Int cells was studied as well by MTT assay.
RESULTS: The mucoadhesive and absorption enhancement properties of chitosan and the protective effect of methacrylic acid-methyl methacrylate copolymer against rHuKGF release at the stomach, low pH, were combined to promote and ensure rHuKGF intestinal delivery and increase serum levels of rHuKGF. In addition, in-vitro studies revealed the protein bioactivity since rHuKGFloaded CNPs significantly increased the proliferation of FHs 74 Int cells.
CONCLUSION: The study revealed that oral administration of rHuKGF-loaded CNPs in methacrylic acid-methyl methacrylate copolymer-coated capsules is practically alternative to the IV administration since the absolute bioavailability of the orally administered rHuKGF-loaded CNPs, using the rabbit as animal model, was 69%. Fluorescent microscope imaging revealed that rhodaminelabelled rHuKGF-loaded CNPs were taken up by FHs 74 Int cells, after 6 hours' incubation time, followed by increase in the proliferation rate.